Answer:the drug is a small non polar molecules
Explanation:the membrane of human cells is a lipid bilayer membrane.this property of the cell regulates the type of substances they can enter into it.a cell is constantly in interaction with it's external environment and needs to take in materials for growth and metabolism.this movement in and out of the cell is determined by the
difference in the concentration of materials, in and outside of the cell.
Some molecules which are small and non polar can easily pass through the cell membrane.this is called simple diffusion.this is so because these small molecules can easily diffuse through the lipid bilayer of the cell membrane.
Molecules such as oxyhemoglobin gas, nitrogen gas ,carbon dioxide can easily pass through .
Thus the drug been discussed must be small and non polar